It is known with mineral winning machines, such as ploughs, which work by skimming or stripping a face as well as with machines such as shearers or partial cutting machines which have rotatable cutting heads to have cutters detachably supported in holders. These assemblies have been proposed in numerous constructions but only a comparative few of these have been adopted in practice. Normally the cutters are subjected to high load, particularly impacts, and wear and the cutters need replacement frequently sometimes even after just one working shift. The cutters need to be secured in their operating position reliably and yet the securing means must allow rapid release and replacement of the cutters. The securing means must also cope with the usual harsh and cramped conditions encountered in underground mine workings. Securing means of various kinds have been proposed such as pins, screws, keys, liners, sleeves, resilient or otherwise, multi-part or otherwise or combinations of these--see DE-PS 1239647, DE-GM 1941306, DE-OS 3242144, DE-AS 2244977, DE-OS 3209410, DE-GM 8633094, DE-OS 2929852 and DE-AS 1188016.
In the case of a coal plough, where accessibility is aggravated when the plough is standing close to the coal face, wedge elements has been used as a securing means for clamping the cutter bits in their holders, see DE-OS 3440448. Precautions must be taken in practice to prevent the wedge elements from becoming slack and falling out of the holders and this means that a rapid and trouble-free release for cutter bit replacement is not always possible.
A general object of the invention is to provide an improved cutter bit assembly and more particularly an improved means for securing the cutter bit in a holder.